Conventionally, there have been known power modules in which a power chip including a semiconductor device such as Insulated Gate Bipolar Transistor (IGBT) is mounted on a leadframe therein, and of which the whole system thereof is molded with resin, as one of semiconductor modules. Since such a semiconductor device produces heat during an operating state, it is common to dispose a heat sink via an insulating layer on a back side surface of the leadframe in order to cool the semiconductor device.
Moreover, there has also been known a thermal dissipation structure of contacting a heat sink to a cooling apparatus in order to improve cooling performance.